全文获取类型
收费全文 | 108125篇 |
免费 | 8388篇 |
国内免费 | 9057篇 |
专业分类
125570篇 |
出版年
2024年 | 240篇 |
2023年 | 1418篇 |
2022年 | 3262篇 |
2021年 | 5512篇 |
2020年 | 3779篇 |
2019年 | 4680篇 |
2018年 | 4431篇 |
2017年 | 3239篇 |
2016年 | 4592篇 |
2015年 | 6681篇 |
2014年 | 7856篇 |
2013年 | 8304篇 |
2012年 | 9984篇 |
2011年 | 8987篇 |
2010年 | 5554篇 |
2009年 | 4985篇 |
2008年 | 5720篇 |
2007年 | 5145篇 |
2006年 | 4463篇 |
2005年 | 3498篇 |
2004年 | 2971篇 |
2003年 | 2725篇 |
2002年 | 2276篇 |
2001年 | 1868篇 |
2000年 | 1696篇 |
1999年 | 1670篇 |
1998年 | 1037篇 |
1997年 | 1003篇 |
1996年 | 944篇 |
1995年 | 828篇 |
1994年 | 791篇 |
1993年 | 617篇 |
1992年 | 820篇 |
1991年 | 618篇 |
1990年 | 466篇 |
1989年 | 443篇 |
1988年 | 354篇 |
1987年 | 344篇 |
1986年 | 266篇 |
1985年 | 286篇 |
1984年 | 156篇 |
1983年 | 161篇 |
1982年 | 99篇 |
1981年 | 85篇 |
1980年 | 60篇 |
1979年 | 77篇 |
1977年 | 59篇 |
1975年 | 56篇 |
1974年 | 52篇 |
1973年 | 56篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
Wang Haili Xu Yuanyuan Xu Aiqing Wang Xinghua Cheng Lijun Lee Sharen Tse Gary Li Guangping Liu Tong Fu Huaying 《Journal of physiology and biochemistry》2020,76(4):637-653
Journal of Physiology and Biochemistry - Atrial remodeling in diabetes is partially attributed to NF-κB/TGF-β signal transduction pathway activation. We examined whether the... 相似文献
994.
Ju Zhou Qing Lan Wu Li Lin Yang Jing You Yan‐Mei Zhang Wei Ni 《Cell biology international》2020,44(1):108-116
To investigate the roles of tripartite motif containing 52 (TRIM52) in human hepatic fibrosis in vitro, human hepatic stellate cell line LX‐2 cells were transfected with hepatitis B virus (HBV) replicon to establish HBV‐induced fibrosis in LX‐2 cells, and then treated with small interfering RNA‐mediated knockdown of TRIM52 (siTRIM52). LX‐2 cells without HBV replicon transfection were treated with lentiviruses‐mediated overexpression of TRIM52 and phosphatase magnesium dependent 1A (PPM1A). Fibrosis response of LX‐2 cells were assessed by the production of hydroxyproline (Hyp) and collagen I/III, as well as protein levels of α‐smooth muscle actin (α‐SMA). PPM1A and phosphorylated (p)‐Smad2/3 were measured to assess the mechanism. The correlation between TRIM52 and PPM1A was determined using co‐immunoprecipitation, and whether and how TRIM52 regulated the degradation of PPM1A were determined by ubiquitination assay. Our data confirmed HBV‐induced fibrogenesis of LX‐2 cells, as evidenced by significant increase in Hyp and collagen I/III and α‐SMA, which was associated with reduction of PPM1A and elevation of transforming growth factor‐β (TGF‐β), p‐Smad2/3, and p‐Smad3L. However, those changes induced by HBV were significantly attenuated with additional siTRIM52 treatment. Similar to HBV, overexpression of TRIM52 exerted promoted effect in the fibrosis of LX‐2 cells. Interestingly, TRIM52 induced the fibrogenesis of LX‐2 cells and the activation of TGF‐β/Smad pathway were significantly reversed by PPM1A overexpression. Furthermore, our data confirmed TRIM52 as a deubiquitinase that influenced the accumulation of PPM1A protein, and subsequently regulated the fibrogenesis of LX‐2 cells. TRIM52 was a fibrosis promoter in hepatic fibrosis in vitro, likely through PPM1A‐mediated TGF‐β/Smad pathway. 相似文献
995.
Ming‐Ming Guo Wen‐Long Wang Hong‐Liang Kang Bo Yang Jian‐Ming Li 《Restoration Ecology》2020,28(1):104-114
Revegetation represents an effective measure for preventing soil erosion on the Loess Plateau. However, the effects of revegetation‐induced changes in soil and root properties on soil resistance to concentrated flow erosion (SRC) remain unclear. This study sampled soils and roots across a 25‐year chronosequence from farmland to grasslands of different ages (3, 7, 10, 18, and 25 years) to quantify variations in soil and root properties (soil bulk density, SBD; soil disintegration rate, SDR; saturated hydraulic conductivity, SHC; organic matter content, OMC; water‐stable aggregate, WSA; mean weight diameter, MWD; root mass density, RMD; root length density, RLD; and root surface area density, RSAD) and their effects on SRC. Farmland and grassland SRCs were obtained using a hydraulic flume. Soil properties and root density gradually improved with restoration time. In terms of the comprehensive soil property index calculated via principal component analysis, grassland values were 0.66 to 1.94 times greater than farmland values. Grassland SRCs increased and gradually stabilized (>18 years) over time and were 1.60 to 8.26 times greater than farmland SRC. SRC improvement was significantly related to increases in OMC, SHC, WSA, and MWD and decreases in SBD and SDR over time. SRC was effectively simulated by the Hill curve of RMD, RLD, and RSAD. SDR, SHC, and RMD (0.5–1.0 mm) affected SRC the most. This study scientifically describes how revegetation improves soil quality and soil resistance to flow erosion, and suggests that vegetations rich in 0.5–1.0 mm roots should be preferred during revegetation. 相似文献
996.
Li X. B. Titlyanov E. A. Titlyanova T. V. Belous O. S. Xia J. Q. Huang H. 《Russian Journal of Marine Biology》2020,46(6):485-492
Russian Journal of Marine Biology - Intensive algal sampling was conducted from 2017 to 2019 in coastal waters of Wuzhizhou Island (South China Sea, China). In total, 183 species of marine... 相似文献
997.
Ming‐Yuan Du Jia‐Xi Duan Chen‐Yu Zhang Hui‐Hui Yang Xin‐Xin Guan Wen‐Jing Zhong Yan‐Zhe Liu Zi‐Ming Li Yu‐Rui Cheng Yong Zhou Cha‐Xiang Guan 《Cell biology international》2020,44(1):98-107
Idiopathic pulmonary fibrosis (IPF) is a progressive disease characterized by excessive deposition of extracellular matrix (ECM) and chronic inflammation with limited therapeutic options. Psoralen, a major active component extracted from Psoralea corylifolia L. seed, has several biological effects. However, the role of psoralen in IPF is still unclear. Here, we hypothesized that psoralen played an essential role in IPF in the inhibition of fibroblast proliferation and inflammatory response. A murine model of IPF was established by injecting bleomycin (BLM) intratracheally, and psoralen was administered for 14 days from the 7th to 21st day after BLM injection. Our results demonstrated that psoralen treatment reduced body weight loss and improved the survival rate of mice with IPF. Histological and immunofluorescent examination showed that psoralen alleviated BLM‐induced lung parenchymal inflammatory and fibrotic alteration. Furthermore, psoralen inhibited proliferation and collagen synthesis of mouse fibroblasts and partially reversed BLM‐induced expression of α‐smooth muscle actin at both the tissue and cell level. Moreover, psoralen decreased the expression of transforming growth factor‐β1, interleukin‐1β, and tumor necrosis factor‐α in the lungs of BLM‐stimulated mice. Our results reveale for the first time that psoralen exerts therapeutic effects against IPF in a BLM‐induced murine model. 相似文献
998.
Chen S. L. Zhang L. P. Cai X. M. Bian L. Luo Z. X. Li Z. Q. Ge L. G. Chen Z. M. Xin Z. J. 《Russian Journal of Plant Physiology》2020,67(3):572-580
Russian Journal of Plant Physiology - The tea geometrid Ectropis grisescens is an important pest of tea plant (Camellia sinensis (L.) O. Kuntze). It feeds on the new leaves and tender... 相似文献
999.
Russian Journal of Plant Physiology - Organisms can produce heat shock proteins (HSPs) in response to elevated temperatures and other abiotic stresses. However, the function of HSPs, including... 相似文献
1000.
Yang H. Y. Dong S. S. Zhang C. H. Wu W. L. Lyu L. F. Li W. L. 《Russian Journal of Plant Physiology》2020,67(1):76-84
Russian Journal of Plant Physiology - Tocopherol (vitamin E) is widely recognized as a cellular antioxidant and can prevent oxidative damage during seed quiescence and dormancy in all angiosperms.... 相似文献